1. Field of the Invention
The invention is in the general field of improved methods of pumping viscous hydrocarbons through a pipe, such as a well-bore or a pipeline.
2. General Background
The movement of heavy crudes through pipes is difficult because of their high viscosity and resulting low mobility. One method of improving the movement of these heavy crudes has included adding to the crude lighter hydrocarbons (e.g. kerosine distillate). This reduces the viscosity and thereby improves the mobility. This method has the disadvantage that it is expensive and the kerosine distillate is becoming difficult to obtain.
Another method of improving the movement of these heavy crudes is by heating them. This requires the installation of expensive heating equipment and thus is an expensive process.
The use of oil-in-water emulsions, which use surfactants to form the emulsion, is known in the art.
U.S. Pat. No. 3,943,954 teaches lowering the viscosity of viscous hydrocarbons by adding an aqueous solution containing an anionic surfactant together with a quanidine salt and optionally with an alkalinity agent and/or a nonionic surfactant. The patent teaches that the guanidine salt is required.
Commonly assigned copending application Ser. No. 13,358, filed Feb. 21, 1979, discloses a method of transporting a viscous hydrocarbon through pipes wherein the method uses water containing an effective amount of an alkaryl sulfonate having a molecular weight below about 410. The application contains data which shows that high molecular weight sulfonates are not effective in the method.
We have found that using a C.sub.1 -C.sub.4 alcohol with an alkaryl sulfonate having a molecular weight of about 415 to about 470 provides a composition, which when used in water and added to a viscous hydrocarbon, provides a reduction in viscosity.